Recently, the number of computation intensive programs increases exponentially. It requires the high-quality computation hardwares and large amount of energy, whereas the computation capability and the battery capacity of mobile devices are restricted. To resolve this issue, mobile computation offloading (MCO) is the one of hottest research topics. A mobile offloads some part of or the entire program to the cloud server, and the program is remotely executed in the could server. As a result, the mobile can save its computation energy.